1. Technical Field
This disclosure relates to a wheel hub configured to accept different types of hubcaps. More specifically, this disclosure relates to a hybrid wheel hub (e.g., for large trucks) configured to accept a threaded screw-on hubcap or a bolt-on hubcap. This disclosure also relates to an adaptor configured to allow a bolt-on wheel hub to accept a threaded screw-on hubcap.
2. Description of the Related Art
Generally, a wheel hub has a roughly cylindrical barrel with an axial bore for receiving an axle of a vehicle. The barrel has an outboard end oriented away from the axle and an inboard end oriented toward the axle. The inner surface of the axial bore includes an outer bearing cup for retaining an outboard bearing assembly and an inboard bearing cup for retaining an inboard bearing assembly. The outboard and inboard bearing assemblies support the axle. A hubcap is attached to the wheel hub at the outboard end to secure the outboard bearing assembly within the outboard bearing cup.
Generally, there are two types of hubcaps: bolt-on hubcaps and threaded screw-on hubcaps. Bolt-on hubcaps include a pattern of bolt holes geometrically spaced around the perimeter of the hubcap, and configured to receive cap bolts. Screw-on hubcaps generally include a continuous sidewall that is threaded on its outer surface.
Wheel hubs are conventionally designed to accept one of these hubcap types, but not both. For example, a wheel hub configured to accept a bolt-on hubcap (i.e., a “bolt-on wheel hub”) includes a plurality of wheel hub bores or bolt holes symmetrically disposed around the perimeter of the outboard end. A bolt-on hubcap is thus attached to the bolt-on wheel hub by threading cap bolts through the apertures disposed about the perimeter of the hubcap and into corresponding wheel hub bores. An example of a bolt-on wheel hub is shown in FIG. 1 of U.S. Pat. No. 6,866,345 to Fakhoury et al. In a wheel hub configured to accept a threaded screw-on hubcap (i.e., a “screw-on wheel hub”), a portion of the axial bore extending between the outboard end and the outboard bearing cup is internally threaded. A screw-on hubcap is thus attached to the screw-on wheel hub by threadedly engaging the sidewall of the hubcap with the portion of the axial bore. An example of a screw-on wheel hub is shown in FIG. 1 of U.S. Pat. No. 6,758,531 to Bullard.